This is your quintessential isolated survivalist thriller in the same vein as Fall, Frozen, The Shallows and the like. Unfortunately, due to a few different things, I don't think it was quite as successful as its predecessors.
Right off the bat, I noticed two things... The picture quality was quite nice and the acting was a little... sus. There were some genuine, real to life moments and interactions with everyone involved while also having some clunky, robotic ones and that aspect persisted throughout the film. I think this was mainly due to some spotty acting and a not super refined script.
As far as the play-by-play goes, I would say these films are some of the hardest to retain your viewers engagement throughout as it is often just a single setting with not all that much to explore or come up with. I think the foundation of what they had as far as action within the "predicament" was there but the pacing slowed down at points throughout and the ending began to drag.
A pretty big issue I had with this one was that there was a lack of consistency within the variables in this world. Sometimes the quicksand and its viscosity looked easy to navigate and sometimes impossible, somethings seemed to effect one person and their health more than it effected the other, at one point an object may seem too far and unattainable and suddenly with a seemingly unhelpful alteration it is now within reach.
I am not a particularly picky reviewer, and am all for letting things go for the sake of entertainment. However, small things such as these and lapses in continuity provide for a heavy does of suspension of disbelief to be enjoyed.
This was by no means an unsuccessful film or entirely unentertaining, but I definitely think it had some major issues that squandered some of the its potential and were detrimental to its success. I think this landed just below average at a 4.5 rounding down to a 4. Would recommend, but not with any fervency.